Synthesis and properties of the ivyanes: the parent 1,1-oligocyclopropanes

Practical syntheses of the first six members of the ivyane (1,1-oligocyclopropane) family of fundamental hydrocarbons have been achieved from the cross-conjugated polyenes known as dendralenes. Evidence for helical conformations in both the solid state and in solution is presented. [6]Ivyane exhibits one of the highest experimental heats of combustion recorded for a hydrocarbon. Ring-opening reactions of ivyanes furnish new and interesting structures that are difficult to access by conventional means.